The Environmental Protection Agency and the Food and Drug Administration reported higher-than-normal levels of radioactive Iodine-131 in milk samples from California and Washington Wednesday. But the levels are 5,000 times below the danger threshold.

"These types of findings are to be expected in the coming days and are far below levels of public health concern, including for infants and children," the EPA said on its website.

A March 25 radiation reading from milk in Spokane, Wash. -- 0.8 picocuries per liter -- is more than 4,000 times less than that of a normal banana, which naturally contains radioactive potassium.

"Radiation is all around us in our daily lives, and these findings are a minuscule amount compared to what people experience every day," FDA senior scientist Patricia Hansen said in a statement.

A person would have to drink almost 1,500 gallons of milk -- two firetrucks full -- in eight days to reach the conservative safe limit.

"Radioactivity levels in milk products are monitored, so it is unlikely that any significantly contaminated milk would make it to the marketplace," said Dr. Timothy Jorgensen, associate professor in the department of radiation medicine at Georgetown University Medical Center. "The U.S. population need not be concerned about this level of Iodine-131."

On March 28 the EPA reported very low levels of radiation in the air over Alaska, Alabama, California, Hawaii, Idaho, Nevada, Saipan, Guam, Northern Mariana Islands and Washington state.

"The major food concern is with milk, because the I-131 gets concentrated in cow milk, when cows eat I-131 contaminated grass," Jorgensen said. "So although other foods might contain I-131, the major route of human exposure would be through milk products."

On March 22, the FDA banned milk and produce imported from Japan's Fukushima, Ibaraki, Tochigi and Gunma prefectures.

Jorgensen said the levels of radioactive iodine in milk on the West Coast do not warrant the use of potassium iodine tablets.

"It is possible to overdose on potassium iodine tablets, particularly if small children are given adult doses," Jorgensen said. "It is best to follow the advice of public health officials with regard to both food consumption and potassium iodine use."

Radiation Fears in U.S. Still High

Despite reassurance from various governmental agencies, public fears about radiation in the U.S. persist.

"It's very hard to head about radiation and iodine in milk and not be concerned. It sounds scary," said ABC News chief health and medical editor Dr. Richard Besser in an interview on ABC News' "Good Morning America."

But Besser said the ongoing monitoring efforts mean problems would be reported very quickly to the public. And as the situation at Japan's crippled nuclear plant improves, the levels will drop dramatically.

"Once they're able to control this reactor, radioactive iodine does not stay around for very long," Besser said. "The half life is eight days, and so after 80 days it's gone from the environment."